Underreamer for oil wells



Sept. 7, 1943.' H. P. MILLER UNDER REAMER FOR OIL WELLS Filed April 7, 1941 m C jS WM p. Y M.

. This invention, relate-sto and Tfor "arioli`` hols and icultiinl aliningtle new 'holes ject;v the proVision-of an improved: Teaming de# arise by` rezisnfv ofs'uch obstacles, vespecially in Vice for `olli and Water'WeI-ls-of;simplfecoiiomical ci-SesY Where tnefolc'l holes vfee' notstraight. A It and: advantageous `rclfretraci:ter whichs applicable is anon-ject, tlierefore,` to" iii"oi/"idel ininyi'rnfprovfcf to' drilling purposes in;thefsamfel manner as con- 51..:a1'15aratufsl asuitble ine'ansl for maintaining tl'ie Ventiona-l reameisy but inolues. dentali@ novel? features` Whinh vrenders the devlcemete e'fcaoiou Y Brief-regardless-oflstriictins-faiid intersections Afparticular object is to vprovide reamingf del -f Vice embodyinga rotatable mandrel adapted `forV attachment to'y andfor rotaltitltyithe drilling? stem of a; rig, `aird fa: bdyfmmleiicoaxal' vvitli y K afndlatleast partiallyjencl'osingthe mandrel; oi-' `riplflery ofthe reainer a portion ltl'flereo andwinsertllcle in the cli'ill'ngA lilbody but are` spaced' downwardly for a suitable string upwardly of tlfiedil'llng bit; iil including di-starefllovl thev "r'dereamers and are deaw pluralityLof reamfins tools.- tilt'alolyi mounted! o n than the conventional. andwell lrlowritypesof? erativ daine'ter Vsubstanj theperiphery o f the bodysoastoswngloutttardly "ally corre pndi fr thatof the hole dug at their upper' extremities. 'firoml aiie's 'at their the bit Wliicli S' Still Ie'lvi th auxiliary reamer's;

"ated ran'er body rias two spaced g"`inftlie I'iOle in addition to the l? position 'upon a; slight rrstatim er niej mandi. tlaey direction' of rotation ofl the? :l-'fill` fstih'g v l at such pointstb' lck tl'le 'mandrel arid` bod-yirg my' imp body togetherforcommof'rotatiiim A 1 AA further* oljectislt poiiid/iis for tuA l l matically retractingl theeain 'ifib'ndet u title ijrit1`di"imfention positions to" psitisn's wit .n trie'- body upma reverse rotation ot. the nandre?.I f l: Another objectgii'sl tov provide" suitale stdff operatively positioned in a well; i

ers retracted;

1 "149.ing` the underreamers exte'iiiedj l iofrre 1 l ing devices and on occasions-g. particularly-With the use of VcertainV ,apparatf1s,. thelfuid. free accessto-tlie-'interio1.ef` the reaning apparatus Y l V and thereby causes trouble and: ilel'ztlysy by 'tlef 45f-encou1f1'tei'edfb ne drillingaidreannngpmt, fouling-.of themecliaiiisrtr- Witlipgritgnsandl, trusty] 'NS'iShWliiil l e diawiig, the apparatus con` yrermciif seal@ section `of a well in* is isf mounted for use and in yf ld.` intersectingliole' is about to be' 'l Object of this inventio @provide amunderream i both1- generally itV circular crossV sectiont Sectionv ing apparatus which isfpostively Sealed at itsf if generally Ifffd 'G0' -S :2f mandrel and; is:l top and bottom against vthe entrance of such V50=gattaerlaeletoiasectioii of the drill! stem C as by fluid, and yet is arranged to permit the free flow meansl of an externallytnraled cellar i which" of iiuid through the unit for use in the vicinity oil; is sunniti/eil` into: 'al correspondingly threadeti re-` f the drilling. loit.

cess2u of the@ mandrel. The bqdy section B' is ed.;

and is also counterbored at 4 to receive a reduced extension 5 of the mandrel, as shown in Fig. 1, thereby centering the body and mandrel for operation.

It will be .noted that both the mandrel and body are correspondingly bored at 6 and l, respectively, to receive a pipe 8 which is continuous from a point of communication with the Adrill stem collar I to a point of communication with asimilarcollar. 1.. on drill bit D..1 Bit UD is attached to body Blby means of collar. 'l'. l'

MandrelA and body B are rotatably connected and also held against longitudinal disconnection by means of a' pair of sets of ball bearings 9 and l0 which run inexternal grooves and |.2,re.

spectively, formed on the periphery of the man.

The lower bearing portions of the underreamers are pivotally supported on body B by means of 'I'he reamer supporting brackets have exten- Y sions 36 projecting above the portions'3l which are engaged by nat springs 3'| attached at their upperends to, thebody andV having their lower ends resting against the portions 3|, for tensioning the reamers so as to normally retract the' ""i'reamers from` extended to Tetra-@ted Positions drel and alined internal grooves. 3 and I4, re-

spectively, formed. on the interior Voffbody B, thereby providing frictionless bearings between the two main members of. the apparatus. lThe balls of the two sets ofybearingsv lmay' be in serted in their grooves orremoved therefrom 'asl byfmeans AofV apertures I 5 in .the rannular wall of.,

the body whichthreadedlyzhpld plugs 16,50 that thevba'lls may be inserted or removed, one after.

another, -when said plugsare removed, and-may be retained in operativepositions when the'plu gs' are. screwedxinto the apertures- Y,

lyingthebore 6 of themandrel andgseated in -thegbottcmof a counterboregl. Apackingglandr isfdetachably held inthe counterbore "I8 and includes one or more packing rings |9fiand a com,-

pressing member 26 whichiswthreaded intoA counterbore 8 so as to conne and compress the packing `rings between the flange V|`| and mem#` ber .around the upper end` of vpipe il, so asto prevent leakage of a drilling luidsupplied its -upper end gradually so as yto avoid shoulders or abutments on the exterior of the reamer apparatus, vas is customary in well .drilling'practise. y The lower end of the body is also sealed against the entrance of the drilling fluid, as by means ofU a counterbore 26 in which one or more .packing'rings 2l are compressed -betweenthe end of thezcounterbore and a plugi 28 which is threaded into theend of the body. i ,A

Body B. has` a plurality of vertically orangularly disposed recesses 29 formed4 on theperiph'- `eryv thereof. for adjustably supporting reamer units of which there rmay be any desired numt ber ldepending vupon the' size andV character of the well-theform of device shown illustrating butfthree of such units.

Each underreaming unitE includes a U-shaped bracket having aY flat back portion 39, upper and" lower bearing portions 3| and 32, respectively, and'arotatable reaming tool 33 supported on within the recesses 29.

, The ,lower end ofthe vmandrel A has a cam 38`ther`eon with spiral segments 39 adapted to fffengage 'the inner vsurfaces of the reamer brackets, as shown in Figs. 1 and 4, for extending the mal1y,:the reamer supports will engage the low.

dwells of saidcams andat: such times, the ream`v Theupper endof pipe 8n hasaange lgl--cuiver-l4 a shaft y34 and suitably fluted, ribber or other- Ywise formed for underreaming thewell following the bit D downwardly `in the hole Hand there? by providing'an enlarged and reamed hole] H. 755

:sheets `o1 leather orA reamers to operative' position in the well when the mandrel yhas been rotated sufficiently'. 'Noi'- ers will be within the'limits ofthe hole H but when operationsare instituted the mandrell'will' K be rotated by'the drill-stem Yuntil the cam segments-will have extended the reamers 33at their upperends to al required extent for van under-if reaming operation, andfat such times ther rela` tive rotation of the Amandrel-andlbody will have been stopped dueito the engagementof lugs 40' O11; the Amandrel with lugs f4| on the Ainterior of* the body Other vlugsy 42 .onithemandrel! by reasonof their engagementwith'lugs43 onthe' l interior`V of 'the body ...prevent the retraction of i" thegrnandrel in the body. beyond a predetermined extent; and V serve to establish a-:nonalvrelationship lbetween the mandrel' and `body before thei4 institutionof an underr'eaming; operation. -1 '-f I VAbove each- .of .theA reaming unitsi `E,1I provide i onthe exterior of Vthe body.;B'ivertical'ribs 44v of suitableywidth to-coverfthe upper ends' of the reamers when they;'arein1,retracted positionv in" order that the tool may -be lowered into the drilled hole H made-.bythebit D. yIn this connectiom-' itgmay be Iunderstood ,thatthe overall diameter-"i ofthe tool when the reamersare retracted -does notn exceed the `diameterjof 'the bit D.

l Spaced suitably below the underreamers andi."

mountedonthe bodyB is agsetof auxiliary reamers F corresponding to or moreor-less in number than the underreamers and .which have trunnions 45 and 46 at their topsand bottoms, respectively, for rotatably .supporting the auxiliary rea .ersvonj the body andin recesses 41 formed* serve as an I extra bearing 1in the hole forthe assembled toolfiwhereby 'the toolmay bedirected j, ina-'predetermined course, inv cooperation -wth the bit and theunderreamers.'r

Preferably, the auxiliary reamers aredispose'd at diierent angles,I though not fnecessarily'.' in order that the hole made by the bit may be thoroughly scavenged and smoothed in'its downward tions.

The underreamer thefentrance 0f .the arming fluid by means'ef peripherally onsaid body. The auxiliary reamers are xed. in positioni and serve Ato ream the n hole H madeby the bit D and at` thesame time units are sealed against the like, as at v48," attached e to the backs of the portions -30 of the underreamer supporting brackets and in such a manner that the edges thereof will wipe the marginsl of the recesses 29 and prevent leakage/ofthe'r drilling iuid into the interior of the body B through said recesses, and around the joint between the body and mandrel in the vicinity of the cam 38. r i

Thus, as the tool progresses in its downward movement in the ground the bit digs the hole,

the series of auxiliary reamers sizes the holeand i the series of underreamers enlarges the hole to a desired size for the reception of a well casing, as in other types of reamers.

The combination of the two setsl of reamers mounted on a single body tends to straighten the hole as nearly'as possible and the transition from operative reaming'condition to a nonreaming condition is readily established by re` `tracting the mandrel in the body sufficiently to permit the tension of springs 31to retract the underreamer units to an overall diameter comparable to the hole reamered `by the auxiliary reamers. Hence, the tool in its completeness may be inserted in and removed from a well with facility.

The interior of body B and also of mandrel C is completely packed with grease in order that ample lubrication may be provided between said members for relative rotation thereof and at the same time, the presence of lgrease in any vcavities or chambers of said members will resistv the entrance of the drilling fluid particularly around'the underreamers E and the mountings therefor. What I claim is: Y i l. An underreamer for wells comprising: `a

l body, a mandrel rotatably mounted in said body,

said body having a plurality of recesses formed on the periphery thereof, a chamber being formed in the body near the lower end of the mandrel arranged for communication with the upper eX-r tremities of said recesses, a plurality of rotatable underreamers pvotally supported inthe lower extremities of said recesses for extension above the axes thereof outwardly fromthe body and having portions extending into'said chamber, and means on Vsaid mandrel engageable with the extended portions of the reamers for extending the reamers into operative positions.

.underreamers pvotally supported in the lower extremities of said recesses for extension above the Vaxes thereof outwardly from the body and having. portions extending intosaid chamber, and means on said mandrel engageable with the extended portions of the reamers for extending `the reamers into operative positions, and means on the periphery of the mandrel and on the bore of the body for limiting the relative movement of the Abody and mandrel, for the purpose described.

3. An underreamer for wells comprising: a

body having a major bore in its upper portion and a minor bore in its `lower portion, a mandrel rotatable in said major bore and having a bore corresponding to the minor bore of the body, a

drill stem attachable to the upper end of the body, a drill bit attachable to the lower end of the body, a pipe for drilling fluid held in the minor bore of` the body and in the mandrel and connected with said drill stem and said bit for delivering a iiid'` from said stem `to said bit, a plurality of inclinable and extensible reamers carried on the exteriorof said body, means on the lower portion of said mandrel operatively engageable with said reamers` for extending the same to operative position, means connedbetween the periphery Yof the mandrel and the major bore of the body for preventing the longitudinal separation of the body and mandrel and including corresponding annular grooves, and rotatable elements held in lsaid grooves adapted to be inserted and removed through radialfapertures in the body.

HARRY P. MILLER. 

